Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
31 Cards in this Set
- Front
- Back
|
What does DNA stand for? |
Deoxyribonucleic Acid |
|
|
DNA is composed of building blocks called what? |
nucleotides |
|
|
Each nucleotide is composed of what? (3) |
1. phosphate group 2. sugar (deoxyribose) 3. nitrogen base |
|
|
What are the two base pairings? |
C with G and A with T |
|
|
What is a double helix? |
Two strands of twisted nucleotides |
|
|
What are bases bonded with? |
hydrogen bonds |
|
|
What are the three possible models of DNA replication? (hint. CD's) |
1. Conservative replication 2. Dispersive replication 3. Semiconservative replication |
|
|
How many steps are there to DNA replication (semi conservative method)? |
There are 5 steps |
|
|
What occurs during first step to DNA replication? |
The enzyme helicase unwinds and unzips (breaks down the hydrogen bonds) of the DNA |
|
|
What is the replication fork? |
the point at which the two template strands are separating |
|
|
What occurs during the second step of DNA replication? |
1. a primer is attached to the template strand 2. complimentary nucleotides par up along the original DNA strand (DNA polymerase lll!!!!!) |
|
|
What is the leading strand? |
new strand of DNA synthesized continuously towards the replication fork (forwards) |
|
|
What is the lagging strand? |
new strand of DNA synthesized away from the replication fork in short fragments later joined together (backwards in short fragments) |
|
|
What occurs during the third step of DNA replication? |
Primers are cut out of the lagging strand and are replaced with DNA nucleotides by an enzyme called DNA polymerase 1 |
|
|
What occurs during the fourth step of DNA replication? |
DNA ligase (another enzyme) joins the DNA fragments together |
|
|
What occurs during the fifth and final step of DNA replication |
DNA polymerase (1 and lll) proof-reads to ensure no mistakes have been made |
|
|
What is a protein? |
a long chain of amino acids |
|
|
What are the two main stages of gene expression and protein synthesis? |
transcription and translation |
|
|
What are the two types of RNA? |
mRNA and tRNA |
|
|
What is the function of mRNA? |
is a messenger. takes the code from the nucleus to the cytoplasm; single stranded |
|
|
What is the function of tRNA? |
it carries specific amino acids to the ribosome |
|
|
What is an mRNA codon? |
a triplet of nitrogen bases (nucleotides) |
|
|
What is an anti-codon? |
tRNA that matches the mRNA codon |
|
|
How many steps are there to transcription? |
3 steps (IET) |
|
|
What occurs during the first step of transcription? |
Initiation - RNA polymerase binds to DNA at a specific site near the beginning of a gene (promoter - sequence of A & T) |
|
|
What occurs during the second step of transcription? |
Elongation - RNA polymerase builds single-stranded RNA in a 5' to 3' direction |
|
|
What occurs during the third step of transcription? |
Termination - synthesis of mRNA continues until a termination sequence is reached then mRNA disconnects |
|
|
How many steps are there to Translation? |
3 steps (IET) |
|
|
What occurs during the first step of translation? |
Initiation - a ribosome binds to mRNA while 2 subunits clamp mRNA between it, as well as Ribosome moves in a 5' to 3' direction until it finds a start codon (AUG) |
|
|
What occurs during the second step of translation? |
Elongation - 1. tRNA attaches to mRNA 2. the next in line enters the site. 3. peptide bond forms between two amino acids 4. ribosome shifts over one codon |
|
|
What occurs during the third step of translation? |
when a stop codon is reached, the ribosome - mRNA complex breaks apart releasing the polypeptide chain |
